Sourdough Trail

HARD 7 reviews
#1 of 1 trails in

Sourdough Trail is a 11.2 mile lightly trafficked out and back trail located near Boulder, Colorado that features a river and is rated as difficult. The trail offers a number of activity options and is accessible from June until September. Dogs are also able to use this trail but must be kept on leash.

11.2 miles 1797 feet Out & Back

dogs on leash



mountain biking

trail running



wild flowers


bridge out


4 months ago

1 year ago

I hiked a bit on the segment by Beaver Reservoir this month. There's an extended foot bridge over Beaver creek which is marked "Closed". This seems to be due to some missing/rotted boards and missing hand rail over the deepest part of the creek. It is safer than trying to ford the creek but it's definitely "use at your own risk".

mountain biking
2 years ago

As the description states, mainly used for trail running and mountain biking. This is a very strenuous trail that is not recommended for sight seeing or a nice leisurely family hike. This is a very difficult and extremely rocky trail.

2 years ago

I simply love this trail!! It has been the subject of so many fun stories and adventures like this one: This place has so much to offer and it is great all year around, I make it up here once per year!!!

2 years ago

Uphill trail that is fairly easy hike. About 15 minutes up you are allowed to camp and are currently allowed to have a fire. A buddy and I hiked in about 4 miles and camped over night was a good time and would do it again downhill was super easy!

mountain biking
4 years ago

Exit at University of Colorado Mountain research station, trail up ahead on right. This trail is very strenuous and 90% up hill, when heading north on trail. They call it north sourdough. Their are jagged rocks that cover whole trail all 6 miles up. It is fast down but beware, I am an advanced rider and my wrists killed me at the bottom and I'm on an all mountain bike. Little traffic also. Over all great ride, nice to get out city and hot temps and HIGH in the mountains :) 6/20/2012

mountain biking
6 years ago

My Experience

I started the ride at the Sourdough Trailhead off Country Road 116. The trail was well marked, and I was eager to ride on this sunny day. Within 5 minutes I was puffing, panting and cursing the baby heads, but I kept going, telling myself things could only get better!!.. Well, things only got worse. The lose rocks combined with the root carpet was killing me, and I was having traction issues that forced me into higher gear, a gear that was slightly too high for this ride, and I was knackered with about 2.5 hours ahead of me. I kept my head high, assuring myself it was going to be worth every minute of the grunt. But it never came, after a 2 hour slaughter, I reached the turn around point.. now I knew for sure that I really did not like this trail, it was like riding on a dry creek. Yes, the ride back was much faster, about 40 min. but it was a hell of a bumpy ride, and I was lucky that I actually managed to stay on the bike.
This trail really confuses me, cos quite a few people recommended it, the books say it is the BEST singletrack in the Boulder area, and I read it was a very scenic trail.. ??? I, for the life of me cannot see what is appealing with this trail.. I am even seriously considering doing it again, just to see if I missed something along the way!!

Other Info:

Traffic on Trail : Two Mountain Bikers from Nebraska, and One Down Hiller walking his (very nice) bike
Wild Life : None
Scenery : None at all scenic (in Sept)
Other : This trail is like riding on a dry creek

My Trail Rating : 3 / 10

Trail Stats & Information

Nearby City: Ward
Length: 12.2 total miles
Trail Type: Out-and-Back
Skill Level: Technically moderate. Physically moderate to challenging
Duration: Advanced Riders, 2 2.5 hours; Intermediate Riders, 3 3.5 hours
Season: May to October
Trailhead Elev: 9200 feet
Top Elev: 1020 feet